plasma

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No matter what kind of tools and materials you use in your shop, chances are pretty good that some process is going to release something that you don’t want to breathe. Table saw? Better deal with that wood dust. 3D-printer? We’ve discussed fume control ad nauseam. Soldering? It’s best not to inhale those flux fumes. But perhaps nowhere is fume extraction more important than in the metal shop, where vaporized bits of metal can wreak respiratory havoc.

Reducing such risks was [Shane Wighton]’s rationale behind this no-clean plasma cutter filter. Rather than a water table to collect cutting dross, his CNC plasma cutter is fitted with a downdraft table to suck it away. The vivid display of sparks shooting out of the downdraft fans belied its ineffectiveness, though. [Shane]’s idea is based on the cyclonic principle common to woodshop dust collectors and stupidly expensive vacuum cleaners alike. Plastic pipe sections, split in half lengthwise and covered in aluminum tape to make them less likely to catch on fire from the hot sparks, are set vertically in the air path. The pipes are arranged in a series of nested “S” shapes, offering a tortuous path to the spark-laden air as it exits the downdraft.

The video below shows that most of the entrained solids slow down and drop to the bottom of the filter; some still pass through, but testing with adhesive sheets shows the metal particles in the exhaust are much reduced. We like the design, especially the fact that there’s nothing to clog or greatly restrict the airflow.

Water, high currents, blinding balls of plasma, and a highly flammable gas that’s toxic enough to kill you in three minutes if you breathe enough of it. What’s not to love about this plasma-powered water gas generator?

In all seriousness, [NightHawkInLight] is playing with some dangerous stuff here, and he’s quite adamant about this one being firmly in the “Don’t try this at home” category. But it’s also fascinating stuff, since it uses nothing but a tank of water and an electric arc to produce useful amounts of fuel very quickly. It’s easy to jump to the conclusion that he’s talking about the electrolytic splitting of water into the hydrogen-oxygen mix HHO, but this is something else entirely.

Using a carbon electrode torch connected to his arc welder, a setup that’s similar to the one he used to make synthetic rubies, [NightHawkInLight] is able to strike an underwater arc inside a vessel that looks for all the world like a double-barreled bong. The plasma creates a mixture of carbon monoxide and hydrogen which accumulates very rapidly in the gasometer he built to collect the flammable products produced by a wood gasifier.

The water gas burns remarkably cleanly, but probably has limited practical uses. Unless you live somewhere where electricity costs practically nothing, it’ll be hard to break even on this. Still, it’s an interesting look at what’s possible when plasma and water mix.

Terrestrial radio may be a dying medium, but there are still plenty of listeners out there. What would a commute to or from work be without a check of “Traffic on the Eights” to see if you need to alter your route, or an update of the scores from yesterday’s games? Getting that signal out to as many listeners as possible takes a lot of power, and this dangerous yet fascinating demo shows just how much power there is on some radio towers.

Coming to us by way of a reddit post, the short video clips show a crew working on a 15,000-Watt AM radio tower. They appear to be preparing to do tower maintenance, which means de-energizing the antenna. As the engineer explains, antennas for AM radio stations in the medium-wave band are generally the entire tower structure, as opposed to the towers for FM and TV stations, which generally just loft the antenna as high as possible above the landscape. The fun starts when the crew disconnects a jumper and an arc forms across the clamp and the antenna feed. The resulting ball of plasma acts like a speaker, letting us clearly hear the programming on the station. It’s like one of the plasma speakers we’ve seen before, albeit exceptionally more dangerous.

It’s an impressive display of the power coursing through broadcast towers, and a vivid reminder to not mess with them. Such warnings often go unheeded, sadly, with the young and foolish paying the price. There’s a reason they put fences up around radio towers, after all.

When you look back on the development history of any technology, it’s clear that the successful products eventually reach an inflection point, the boundary between when it was a niche product and when it seems everyone has one. Take 3D-printers, for instance; for years you needed to build one if you wanted one, but now you can buy them in the grocery store.

It seems like we might be getting closer to the day when satellites reach a similar inflection point. What was once the province of nations with deep pockets and military muscles to flex has become far more approachable to those of more modest means. While launching satellites is still prohibitive and will probably remain so for years to come, building them has come way, way down the curve lately, such that amateur radio operators have constellations of satellites at their disposal, small companies are looking seriously at what satellites can offer, and even STEM programs are starting to get students involved in satellite engineering.

Michael Bretti is on the leading edge of the trend toward making satellites more DIY friendly. He formed Applied Ion Systems to address one of the main problems nano-satellites face: propulsion. He is currently working on a range of open-source plasma thrusters for PocketQube satellites, a format that’s an eighth the size of the popular CubeSat format. His solid-fuel electric thrusters are intended to help these diminutive satellites keep station and stay in orbit longer than their propulsion-less cousins. And if all goes well, someday you’ll be able to buy them off-the-shelf.

Join us for the Hack Chat as Michael discusses the design of plasma thrusters, the details of his latest testing, and the challenges of creating something that needs to work in space.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

The simple plasma ball – it graces science museums and classrooms all around the world. It shares a place with the Van de Graaf generator, with the convenient addition of spectacular plasma rays that grace its spherical surface. High voltage, aesthetically pleasing, mad science tropes – what would make a better DIY project?

For some background, plasma is the fourth state of matter, often created by heating a neutral gas or ionizing the gas in a strong electromagnetic field. The availability of free electrons allows plasma to conduct electricity and exhibit different properties from ordinary gases. It is also influenced by magnetic fields in this state and can often be found in electric arcs.

[Discrete Electronics Guy] built a plasma bulb using the casing from an old filament bulb and an ignition coil connected to a high voltage power supply. The power supply is based on the 555 timer IC. It uses a step-up transformer (the ignition coil) driven by a square wave oscillator circuit at a high frequency working as AC voltage. The square wave signal boosts the current into the power transistor, increasing its power.

The plasma is produced inside the bulb, which contains inactive noble gases. When touching the surface of the bulb, the electric arc flows to the point of contact. The glass medium protects the skin from burning, but the transparency allows the plasma to be seen. Pretty cool!

It seems as though every week we see something that clearly shows we’re living in the future. The components we routinely incorporate into our projects would have seemed like science fiction only a few short years ago, but now we buy them online and have them shipped to us for pennies. And what can say we’ve arrived in the future more than off-the-shelf plasma thrusters for the DIY microsatellite market?

Although [Michael Bretti] does tell us that he plans to sell these thrusters eventually, they’re not quite ready for the market yet. The AIS-gPPT3-1C series that’s currently under testing is designed for the micro-est of satellites, the PocketQube, a format with a unit size only 5 cm on a side – an eighth the size of a 1U CubeSat. The thrusters are solid-fueled, with blocks of Teflon, PEEK, or Ultem that are ablated by a stream of plasma. The gaseous exhaust is accelerated and shaped by a magnetic nozzle that’s integrated right into the thruster. The thruster is mounted directly to a PCB containing the high-voltage supplies and control electronics to interface with the PocketQube’s systems. The 34-gram thrusters have enough fuel for perhaps 500 firings, although that and the specifics of performance are yet to be tested.

Imagine if you will that you are enthroned upon the porcelain, minding your own business while doing your business. You’re catching up on Hackaday on your phone – c’mon, admit it – when a whir and a buzz comes from behind you. You sit up in alarm, whereupon your lower back suddenly feels as if someone is scrubbing it with a steel wool pad. Then the real pain sets in as super-hot plasma lances into your skin, the smell of burning flesh fills the bathroom, and you crack your head on the towel bar trying to escape this torture chamber in a panic.

Sound good? Then [Vije Miller]’s plasma-powered toilet air freshener is a must-build for you. We’re not entirely sure where this was going, but the name of the project seems to indicate a desire to, ahem, clear the air near your derrière with the power of ions. While that might work – we’ve recently seen an electrostatic precipitator for 3D-printer fumes – the implementation here is a bit sketchy. The ball of steel wool? It was possibly intended as a way to disperse the ions, but it served as nothing more than fuel when touched by the plasma. The Contact-esque gimballed rings? Not a clue what they’re for, but they look cool. And hats off to [Vije] for the intricate 3D-printed parts, the geartrain and linkages, and the DIY slip rings.